As an electrode catalyst for the anode and cathode of a fuel cell, a technique relating to fine catalyst particles is known, which has a structure that includes a core particle and an outermost layer covering the core particle (so-called “core-shell structure”). For the fine catalyst particles, the cost of the inside of the particles, which hardly participates in a catalyst reaction, can be reduced by the use of a relatively inexpensive material for the core particle.
In Patent Document 1, a method for producing carbon-supported, core-shell type fine catalyst particles that have a core containing palladium and a platinum shell covering the core, is disclosed.